New Member

Had a good first outing, and a great first run in, but broke the diff second pass. We got some great feedback from the car, and once we get the diff fixed should be able to muster up a high 9 second pass. Onto the vids!

Go-Pro View
[video]http://www.youtube.com/v/SCv1n3IHU3Q[/video]

I love this video! Justin was super pumped that we pulled the tires first go out! All of our hard work finally paid off...... at least for one run.
[video]http://www.youtube.com/v/XuBmfIUf89A[/video]

This is what a broken diff looks like!
[video]http://www.youtube.com/v/hkwrdVYOJEo[/video]

Everthing was built by me and a few friends. The car came to me as a roller in pretty rough shape, but we have slowly brought it back to life. The chassis itself is very clean with zero rust, being that it was a texas car.

Car is pretty much in race trim, but driven on the streets once and awhile. Has no heater core, sound deading, or pretty much anything else that doesn't need to be there.

New Member

Lol, well as much fun as it sounds to keep replacing diffs, I think we will have to start looking into something a bit more permanent. Ive been toying with the idea of doing a ford 9" IRS setup for awhile now, so maybe its time to put that plan into action.

New Member

All the link bars have been remade with heim joint ends in 1 1/4" chromoly, as well, the rear track bar is now more of a J shape to clear the 275"s. I also made a strut spacer that brings my silk road coil overs inboard about 1.5" to clear the 275's as well. So I guess the short answer is no, its not a completely stock IRS setup.

To be honest, we probably could have done a 1.3, or a 1.29 60' pretty easy if the diff had of held up. We had only launched with 13psi and the second run we had upped it to around 15 psi.

Its hard to see in this picture, but if you look closely you can see all the link bars

Member

Those heim joints on the link bars look very similar to the ones I ordered from A1 racing, hopefully they function as well as yours do. Moving the struts in and getting the tire further under the car instead of running a bigger offset is a good idea, I imagine it helps center the weight over the rear tires better than if they were further out.

You seem to be one of the few people on here that have managed to get a really good 60' out of these cars, so i appreciate the info! If I can turn a 1.5 I'll be ecstatic.

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Ive gotten tons of help from people on these forums, and other forums, and other local racers so its the least I can do. I also have the specs of my alignment as well, so I'll try and snap a picture of it tonight or tomorrow and post it up if anyone is interested in having a look at it.

The heim joints I used are 5/8's heims with 5/8's through holes. I had to drill out the hole where one of the link bars meets the hub assembly (it has a tapered ball joint style fastener on it). If your careful you can drill it out and use an 8.8 grade bolt in there instead of the tapered shank. When I made the other 2 ends that attach to the hub assembly I made the plates with the same diameter metric bolt that they use from factory.

Then on the sub frame side, I ended up grinding off all the elongated holes and welding in plates with 5/8" drilled holes to lock the heim joint in a static location. From there you can adjust each bar to get your alignment exactly what you want it to be.

Here is 2 of the 3 link bars. The one thing I plan to modify on the straight bar, is to add another adjustment point where the bar meets the u shaped mount. It made it tough to align when I brought it to the shop to do the alignment, having it solid mounted at that end. If you look close, you can also see the mounts to bring the shocks inboard as well.

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The goal for this year is to go 8.999999999 lol. Not sure how attainable that is on this diff, but we will try. From my logs, this converter stalls at 3900 rpm. If I used some thicker fluid I could probably get that down another 2-300 rpm if I wanted. Yes, the launch was off of a trans brake.

Member

What coilovers and spring rate u running? Nice pass by the way. What kind of power u making? What turbo is that? What gear u running in the diff ? Hoping to get into the 9's with a 7M attached to a th-400.

New Member

They are silk road coil overs with 18kg front / 10kg rear springs. From the trap speed and ET Id say we are making 500-550ish whp through the th400. We are using a pre 89 lsd diff with 3.73 gears in it. I had shimmed the lsd to be a bit tighter, and also put a solid pinion spacer in it. Unfortunately it only lasted 2 passes at 1.31 60'. Like I mentioned earlier, we had upped the launch boost 3-4 psi, and I really think we could have done a 1.3-1.29 60' on the next pass. For now though, we'll probably try and get it to 60' in the 1.4 to 1.5 range and hopefully keep the diff together for the season.

New Member

They are silk road coil overs with 18kg front / 10kg rear springs. From the trap speed and ET Id say we are making 500-550ish whp through the th400. We are using a pre 89 lsd diff with 3.73 gears in it. I had shimmed the lsd to be a bit tighter, and also put a solid pinion spacer in it. Unfortunately it only lasted 2 passes at 1.31 60'. Like I mentioned earlier, we had upped the launch boost 3-4 psi, and I really think we could have done a 1.3-1.29 60' on the next pass. For now though, we'll probably try and get it to 60' in the 1.4 to 1.5 range and hopefully keep the diff together for the season.

New Member

It shouldnt. We will lower our launch boost, but start ramping more boost in after we get past the 60' mark, or as soon as we can depending on what the track will hold.

We are planning to run up to 30-35 psi, so hopefully that should be good enough for a mid to low 9 second pass. Then at the end of the season, we'll raise the launch boost again and see if we cant make a go at a high 8 second pass.

New Member

Its a BW S475. Its basically a 75mm turbo with the largest T6 turbine housing they make for it. We made a few more hits last year and bettered our MPH, but we had a ton of issues getting the launch dialed in (and not breaking diffs). The best I could do was 10.88 at 134mph at 21lbs of boost.

We only 60'd 1.5-1.6 and couldnt get it down any further because of nitrous issues.